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.
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.
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