No abstract

A study was made of the distribution of primary thyroid failure, indicated by a raised serum TSH concentration, in 605 (294 males and 311 females) insulin-dependent (type I) diabetics, aged 21-84 yr, not previously suspected of having thyroid disease. The prevalence of a raised serum TSH concentration in females of all ages (17%) was significantly greater (P less than 0.0005) than that in males (6.1%) and increased with increasing age at onset of diabetes (P less than 0.05) and age at time of study (P less than 0.001) in females but not in males. There was no significant difference in the duration of diabetes when comparing patients with normal and raised serum TSH concentrations. The prevalence of a raised TSH concentration in late-onset insulin-dependent diabetics was no greater in patients requiring insulin within 3 months of diagnosis of diabetes than in those exhibiting secondary sulfonylurea failure, who required insulin more than 3 months after diagnosis. In type I diabetes, the prevalence of subclinical primary thyroid failure is considerably greater than has previously been suspected, with female late-onset insulin-dependent diabetics being at the greatest risk.

No abstract

Neuroendocrine challenge tests of hypothalamic dopamine receptor function in the early postpartum period suggest that the sensitivity of these receptors is increased in women with a history of bipolar disorder after childbirth. We tested the hypothesis that, in women predisposed to bipolar disorder in the puerperium, hypothalamic dopamine receptor function is more sensitive to changes in circulating ovarian hormone concentrations than in women without such histories. Eight fully recovered and drug-free women who had had at least one episode of bipolar illness following childbirth were compared with nine normal controls. Growth hormone (GH) responses to apomorphine (APO 0.005 mg s.c.) were measured in the early follicular phase, when plasma concentrations of ovarian hormones are low, and in the mid-luteal phase, when they are relatively high. The recovered bipolar subjects and the controls did not differ from each other in their follicular and midluteal oestrogen and progesterone concentrations. In the midluteal phase, both groups had increased oestrogen and progesterone levels. The recovered bipolar subjects did not differ from controls in baseline concentrations of GH in either of the menstrual phases. The APO-GH responses of the two groups did not differ in the follicular phase, but in the midluteal phase, when female sex steroids are relatively increased, the recovered group had significantly enhanced APO-GH responses [MANOVA for repeated measures: (i) area under the curve, group by phase effect: p < 0.04; (ii) GH peak rise after APO, group by phase effect: p < 0.056] and the responses were not related to concurrent measures of mood. The results of this small study of women predisposed to bipolar disorder in the puerperium shows an increased dopaminergic receptor sensitivity in the luteal phase of the menstrual cycle. It suggests that their dopaminergic systems have increased sensitivity to changes in circulating female sex steroids. This may be aetiologically relevant to the pathogenesis of puerperal bipolar disorder.

SUMMARY The oral clonidine test was compared with the standard intravenous insulin hypoglycaemia test in 41 children and adolescents with short stature. In those without growth hormone deficiency clonidine provoked a significantly higher mean plasma growth hormone response and gave fewer false subnormal responses (apparent growth hormone deficiency) than insulin. Children with psychosocial deprivation had poorer responses to both tests. In view of these findings and the absence of unacceptable side effects with clonidine it is concluded that the oral administration of this alpha-adrenergic stimulant is a safe and reliable alternative test of growth hormone release.

The oral administration of bromocriptine 5 mg 6-hourly to twelve patients with acromegaly for a mean period of 12 (range 3-27) months significantly reduced whole blood glucose, plasma insulin and plasma growth hormone (GH) concentrations during a 50 g oral glucose tolerance test (OGTT). After this period of treatment, bromocriptine was withdrawn for 48 h resulting in a significant rise in whole blood glucose, plasma insulin and plasma GH concentrations during a repeat OGTT. It is concluded that bromocriptine therapy improves glucose tolerance in acromegaly by suppressing GH secretion and consequently GH-mediated antagonism of insulin.

Objectives-To investigate urine neop-

The response of PRL to the oral administration of the dopamine receptor-blocking agent metoclopramide and the effect of metoclopramide on the TRH-induced release of PRL and TSH were measured in eight patients with hyperthyroidism and in eight age- and sex-matched euthyroid controls. As expected from the known direct inhibitory influence of thyroid hormones on pituitary TSH secretion, there was no TSH rise in response to metoclopramide in either group. PRL levels, on the other hand, rose significantly after the administration of metoclopramide in both the hyperthyroid and euthyroid subjects (P less than 0.0005 at 60 and 120 min). However, the increase in PRL at 120 min was significantly less in the hyperthyroid subjects than in the euthyroid controls (P less than 0.0025). Furthermore, the administration of metoclopramide failed to reestablish normal responsiveness of either PRL or TSH to TRH in the hyperthyroid subjects. We have previously suggested that thyroid hormones inhibit PRL secretion by stimulating the hypothalamic secretion of dopamine. These results suggest, however, that elevated levels of thyroid hormones also inhibit PRL release directly at the anterior pituitary level.