The effects of lesions in the basal medial hypothalamus and limbic structures on the responses in plasma levels of insulin and glucose to daily repeated cold exposure in rabbits have been investigated. The results obtained were summarized as follows: (1) The 1st cold exposure (cold exposure on the 1st day) decreased insulin levels and increased glucose levels, and these responses of insulin and glucose to cold exposure gradually decreased and then completely abolished by daily repetition of exposures in intact rabbits and each sham-operated group. (2) The lesions of periventricular arcuate nucleus (ARC), stria terminalis (ST) and dorsal fornix (FX) had no effects on the insulin responses to the 1st cold exposure, but the rates of insulin responses to the 1st cold exposure were decreased by the lesions of ventromedial hypothalamus (VMH). (3) The ARC lesions had no effects on the glucose responses to the 1st cold exposure, but the glucose responses to the 1st cold exposure were abolished by VMH lesions and were altered by lesions of ST and FX. (4) The insulin responses to cold exposure were abolished by daily repetition of exposures in rabbits with ARC lesions as same in the cases of sham-operated animals, but the insulin responses to cold exposure persisted even after daily repetition of exposures in rabbits with lesions of VMH, ST and FX different from sham-operated animals. (5) The glucose responses to cold exposure were abolished by daily repetition of exposures in rabbits with lesions of ARC and ST as same as in the cases of sham-operated animals, but the glucose responses to cold exposure persisted even after daily repetition of exposures in rabbits with FX lesions different from sham-operated animals.
The pyruvate metabolic response to the 1st exposure (exposure on the 1st day) to immobilization stress (IMO) were considerably altered by lesions of the periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). The pyruvate metabolic responses to IMO were completely abolished by seven times repetition of exposure to IMO in the rabbits with lesions of ARC and VMH; they were similar to sham-operated groups. In rabbits with lesions of ST and FX, the pyruvate metabolic responses to the 7th exposure (exposure on the 7th day) to IMO were almost the same as those after the 1st exposure to IMO, but these metabolic responses were completely abolished by the seven times repetition of exposure to IMO in the sham-operated animals. These results suggest that firstly the ARC, VMH, amygdala (AMYG)-ST system and dorsal hippocampus (HPC)-FX system are involved in the pyruvate metabolic responses to the 1st exposure to IMO, and secondly, that the AMYG-ST system and the HPC-FX system are involved in the disappearance process of pyruvate metabolic responses to IMO by the daily repetition of exposure to IMO.
The effects of lesions in the basal medial hypothalamus and limbic structure upon the responses of adrenocorticoids formation in adrenal slices of rabbits to daily repeated heat exposures has been investigated. (1) The adrenocortical responses to heat exposure on the 1st day were decreased by lesions in the periventricular arcuate nucleus (ARC), ventromedial hypothalamus (VMH), stria terminalis (ST) and dorsal fornix (FX). (2) There were no effects of heat exposure on the 10th day upon the adrenocorticoid formation in either the sham-lesioned rabbits or the rabbits with the lesions of ARC, VMH and ST. (3) In rabbits with the FX lesions, the adrenocorticoids formation was significantly increased by heat exposure on the 10th day. (4) These results suggested that the basal medial hypothalamus, amygdala (AMYG)-ST system and dorsal hippocampus (HPC)-FX system participated in the mechanisms of adrenocortical responses to heat exposure on the 1st day, but only the HPC-FX system played some roles in complete disappearance process of adrenocortical responses to heat exposure by repetition of exposures.
Intact female and neonatally castrated male rats were treated with the dopamine agonist/serotonin antagonist lisuride during the early postnatal differentiation period of the brain (Day 2-12) or during the peripuberal maturation period (Day 26-40). It was found that early postnatal as well as peripuberal activation of the dopaminergic system in females resulted in masculinized social play-fighting behaviour, and lisuride application as late as peripuberally resulted in permanent masculinization of sexual behaviour. Comparable trends were found after peripuberal androgen administration. On the other hand, the demasculinized social play fighting as well as the sexual behaviour of neonatally castrated males, which is usually bisexual or even predominantly heterotypical, could be normalized--at least in part-by early postnatal or peripuberal lisuride administration. These findings confirm once more our previous reports that neurotransmitters can act directly as organizers of the brain. This holds true not only for the differentiation period but also for the maturation period.
STS 557 was tested for adverse effects in mice by prenatal and postnatal investigations. Several doses of STS 557 and levonorgestrel as a standard were administered on days 3--7, 8--12, or 13--17 post coitum. Following administration on days 3--7 p.c. an increase of skeleton retardations and skeleton alterations was found.
The synthetic steroid STS 557 (17 alpha-cyanomethyl-17 beta-hydroxy-estra-4, 9-dien-3-one) was tested in gravid rabbits from days 5 to 25 p.c. It was the aim of the experiments to investigate any embryotoxic and/or teratogenic effect of STS 557. The compound did not show any effects on the mothers nor on the fetuses. Levonorgestrel was tested as standard.
Non-insulin-dependent diabetes mellitus (NIDDM) is a heterogeneous disorder of glucosc horneo stasis characterized by anomalies in the secretion and the metabolic actions of insulin. Present knowledge on the pathogenesis of NIDDM has been reviewed in several comprehensive recent articles (De Fronzo et al., 1992; Dinneen et al., 1992; Editorial Lancet, 1992; Granner & O'Brien, 1992; Häring & Mehnert, 1993; Leahy & Boyd, 1993; Weir, 1993; Taylor et al., 1991). On the basis of this knowledge we shall discuss here theoretical and technical aspects of the current search for the molecular genetic basis of this disease, which has once been called "the nightmare of the medical geneticist" because of the complexity of its genetics (Neel et al., 1965). The familial aggregation of NIDDM and its high concordance rate in identical twins clearly indicate a strong genetic component of the disease (Rich, 1990). From the genetic viewpoint, NIDDM is a "complex" disorder: it has a polygenic genetic background, which predisposes certain individuals for the development of the disease. The clinical course of the disorder, however, is then strongly influenced by non-genetic factors such as lifestyle and nutritional habits. The genetic analysis of complex diseases is far more complicated than the analysis of "classical" monogenic diseases, which are directly caused by defects in a single gene. Significant progress in this field has only recently been made when a wide spectrum of powerful molecular genetic techniques became available, some of which will be outlined later (chapter "Analytical Methods").
In the pregnant mare two different groups of oestrogens are produced by the placenta. The precursor of "classical" oestrogens (oestrone, oestradiol-17 beta and oestradiol-17 alpha) is dehydroepiandrosterone which originates from the fetal gonads. The ring B unsaturated oestrogens (equilin and equilenin and their derivatives) derive from farnesyl pyrophosphate by a pathway not involving cholesterol.
Experiments with animal models have proven that intervention protocols avoiding immunosuppressants can effectively prevent immune-mediated diabetes. These new approaches aim at either supporting the defence of islet cells against inflammatory attack or at modulating the type of the immune response to beta cells towards a more benign quality. Another approach is to reduce the exposure to putative diabetogenic dietary factors during infancy. All of the three strategies are presently tried in clinical studies.
Growth factors are known to take part in the regulation of reproduction. Here we present evidence for the expression of insulin-like growth factor 1 (IGF-1) in the bovine oviduct. Two IGF-1 specific mRNA-transcripts of 1.5 and 4.4 kb were detected during the whole oestrous cycle, and showed increased expression after ovulation. Complete homology to the known IGF-1 sequence was achieved by specific RT-PCR (reverse transcription-polymerase chain reaction) amplification followed by dideoxysequencing of this 210 bp fragment. IGF-1 protein was localized in the secretory cells of the oviduct epithelium using immunohistochemical techniques. We suggest possible effects of IGF-1 during ovulation either on the oviductal cells or on the early embryo.
The aim of this work was to investigate the morphologic changes, LH/hCG receptor content in the ovaries and plasma levels of LH, progesterone and estradiol of hypo--and hyperthyroid rats injected with PMSG and hCG. The hypothyroid state was induced by thyreoidectomy (Tr-X) and the hyperthyroid condition by injections of 40 micrograms L-thyroxine daily during 21 days (T4). Gonadotropins were injected during 14 days in daily doses: PMSG--5 i.u. and hCG--10 i.u. The following 8 groups (n = 10-20) were established: control (euthyroid, no treatment), Tr-X, PMSG + hCG, Tr-X + hCG, Tr-X + PMSG, Tr-X + PMSG + hCG, T4 and T4 + PMSG. At the end of experiments rats were sacrificed, ovaries weighed, macroscopically inspected and concentration of LH/hCG receptors was estimated. In blood plasma the level of LH, progesterone and 17-beta estradiol was also analysed. The experiments showed that injections of PMSG alone, or PMSG + hCG in eu-or hypothyroid rats, appear the most effective in induction of PCO syndrome in rats. Low levels of thyroid hormones sensitized the ovaries to gonadotropin action, but a hyperthyroid status diminished or inhibited this response. Thyroid function is also essential in production of LH/hCG receptors in the ovaries. In hypothyroid animals the amount of these receptors was greatly increased, while in hyperthyroid animals they decreased. The level of plasma LH, progesterone, and estradiol showed insignificantly differences and various inconsiderable deviations from norm. These differences were not dependent on large doses of gonadotropins, altered thyroid function, or on cystic or luteinizing changes in the ovary.
Concentrations of progesterone and estradiol-17 beta were determined throughout pregnancy in 6 to 10 bitches (exp. 1); in experiment 2 peripartal changes of estradiol-17 beta, estrone, progesterone, cortisol, prolactin and growth hormone were determined in 5 bitches; in experiment 3 total unconjugated oestrogens were determined by radioimmunoassay and radioreceptorassay in placental tissue from 25, 53, 60 and 64 days pregnant bitches. No pregnancy specific increase of estradiol-17 beta could be observed; estradiol-17 beta levels decreased prior to parturition concomitant with the decrease of progesterone, suggesting a likewise luteal origin of estradiol-17 beta in the pregnant and non pregnant dog. Cortisol and growth hormone concentrations were elevated at the time of parturition, prolactin concentrations remained unchanged but were higher in pregnant than in non pregnant dogs. No hints in respect to a specific placental oestrogen production were obtained when examining placental tissue. The hypothesis is put forward that the high sensitivity of the haematopoietic system of the dog to oestrogen was an important factor in respect to evolution of endocrine control of pregnancy and parturition in this species which-in respect to placental oestrogen production-seems to be different from most other domestic animal species.
We report about a male patient, who underwent bilateral total adrenalectomy due to ACTH-dependent Cushing's syndrome without pituitary adenoma in his 11th year of life. Symptoms of Cushing's disease were absent during the follow-up period. Height and body weight followed the percentiles 25 and 50 respectively. An endogenous cortisol production was not detected and steroid substitution became necessary. Five years after the surgery, he showed normal cortisol levels, but there was no cortisol increase under ACTH-loading. Nine and 12 years (1993) after surgery, we found normal, physiological levels of cortisol suggestive of normal functioning adrenal glands (day profile of cortisol, Liddle-Test, ACTH-Test, CRH-Test, cortisol excretion in 24-h-urine). Moreover, baseline ACTH and its rise under CRH stimulation were normal. Scintigraphy revealed normal-sized adrenal tissue in orthotopic position on both sides. Steroid supplementation was discontinued. Presently the patient is healthy, active and under no steroid therapy. No evidence of residual or relapsing Cushing's disease or Nelson's syndrome has been found up to this point.
We established a radioimmunoassay (RIA) using anti-PDN-21 antiserum, which was obtained by immunizing rabbits with synthesized PDN-21, and the basic results are described in this report, with discussion of the significance of PDN-21 determination in various thyroid diseases. In this RIA, the double antibody technique was used for B/F separation. This assay yielded excellent standard curves, specificity, recovery and reproducibility showing that the assay is satisfactory from the clinical standpoint. The upper limit of the normal PDN-21 level was 67 pg/ml in 98 healthy persons. Only patients with medullary carcinoma of the thyroid among patients with various thyroid diseases showed specifically positive assay results. The level was 110 to 18,300 pg/ml (mean, 5,940 pg/ml) in 7 patients whose levels were determined preoperatively, and 64 to 140,000 pg/ ml (mean, 10,900 pg/ml) in 18 patients whose levels were determined postoperatively. Thus, PDN-21 levels increased very sharply in the settings of recurrence and tumor residue. These results suggest that PDN-21 has the potential to be an extremely sensitive, highly specific marker for medullary carcinoma of the thyroid.
Two new markers of bone resorption, the collagen cross-linking amino acids pyridinoline (PYD) and deoxypyridinoline (DPD), were measured in 24-h urine collections from 88 healthy children (45 females, 43 males; age 4 to 18 years) and 17 adults. Normal values for pediatric use were established for these parameters. Related to daily excretion of creatinine PYD and DPD were about 3 to 6 fold higher in the pediatric groups than in adults. The collagen cross-links showed a highly significant correlation to the urinary excretion of hydroxyproline (OHP): r = 0.65 for PYD and r = 0.60 for DPD (p < 0.001). Both collagen cross-links and OHP excretion related to creatinine were significantly correlated to growth velocity (r = 0.67, 0.62 and 0.51 for PYD, DPD and OHP respectively; p < 0.001 in each case). PYD and DPD may be useful for the monitoring of growth in children.
The response of the adrenal cortex to a stressor consisting of information about a surgery to be performed the following day was studied in 34 patients by monitoring changes in salivary cortisol. From those, 18 patients were subjected to an individually selected 1 h music program, applied immediately following receipt of the information, and the remaining 16 patients formed a reference group. Another 10 patients, not awaiting surgery, served as controls. Saliva was sampled before the stressor and 5 more samples were collected at 15 min intervals. The stressor produced a 50% rise in salivary cortisol within 15 min. In patients not exposed to music, cortisol levels gradually decreased but after one hour they were markedly higher than the initial level. Listening to music resulted in a marked reduction in salivary cortisol level and after one hour the relative decrease was similar to that observed in control (non-surgical) patients.
Two experiments were conducted to monitor hormonal changes during lactation in crossbred sows (Pietrain x German Landrace). Sows were fed twice daily without weighing the remaining food. Number of piglets was not standardized. Plasma concentrations of growth hormone (GH), prolactin (PRL), insulin-like growth factor-1 (IGF-1), IGF-2, insulin (INS), triiodothyronine (T3), thyroxin (T4), free thyroxin (FT4), non esterified fatty acids (NEFA) and glucose (GLUC) were determined by RIA, EIA or enzymatically. In exp. A (n = 5 sows), blood samples were taken via permanent jugular cannula in weekly 24 h windows at 20 min intervals and additionally once daily for 6 weeks during lactation and for 3 days after weaning. In exp. B (n = 24 sows), blood was collected by needle puncture of the ear vein 2 and 1 week before parturition, the 1st and 3rd-4th week of lactation and 1 and 2 weeks after weaning. GH (0.8 ng/ml) and PRL (10.2 ng/ml) increased with onset of lactation (3.3 resp. 91.5 ng/ml), remained at high levels (2.5-2.8 resp. 39-41 ng/ml) during the 2nd and 3rd week, declined slowly thereafter and considerably after weaning to concentrations of 0.7 resp. 2.7 ng/ml. During lactation in 4 of 5 sows in exp. A, the typical episodic secretory pattern of GH and PRL was lost due to frequent suckling. Basal values, as known from non lactating sows, were not reached and number of pulses was elevated during lactation for both pituitary hormones. Insulin levels showed a high individual variation.(ABSTRACT TRUNCATED AT 250 WORDS)
The oxidation of estradiol to estrone in porcine endometrial cells is succeeded by hydroxylation at either 6 alpha- or 7 alpha-. The products are devoid of receptor affinity. Their formation is inhibited by cytochrome P450 blockers like ketoconazol but not by chloroquine and analogues. The hydroxylation at 6 alpha- proceeds with KM = 1.9 x 10(-7) M, that at 7 alpha- with KM = 3.6 x 10(-7) M. The respective values for the cytochrome P450-reductase cosubstrate NADPH are 1.7 x 10(-5) M and 1.9 x 10(-5) M. The kinetic parameters of the enzymes are compatible with a metabolic sequence: estradiol-->estrone--> 6 alpha/17 alpha-estrone.
