Possible altered dopaminergic modulation of pituitary function in normal-menstruating women with insulin dependent diabetes mellitus (IDDM).

In order to assess whether a possible altered dopamine activity in normal-menstruating diabetic patients may influence the pituitary hormone secretion we have measured the basal serum concentrations of Prl, LH and FSH in 28 patients with insulin dependent diabetes mellitus (IDDM) and in 55 normal-menstruating women at day 3 to 6 of the menstrual cycle. In addition basal levels of oestradiol-17 beta, TSH, thyroxine (T4), triiodothyronine (T3) and resin-T3 uptake (RT3U) were determined in 17 patients with IDDM and in 17 controls. The responses of FSH, LH, Prl, GH and TSH to metoclopramide (MTC) administration (10 mg iv) were studied in 17 patients and 17 controls. In 10 patients with IDDM and 8 controls the short-term variations in pituitary hormones and blood glucose concentration were evaluated. Patients with IDDM had significantly lower basal levels of Prl (P less than 0.01) and TSH (P less than 0.05) and significantly (P less than 0.05) higher basal levels of GH than normal women. No significant (P greater than 0.05) differences were found regarding basal serum concentrations of FSH, LH, oestradiol, T4, T3 and RT3U. During the 3 h period the mean coefficient of variation of Prl, FSH, LH and GH was not significantly (P greater than 0.05) different between diabetic patients and controls. Both groups responded significantly (P less than 0.01) in Prl and TSH to MTC but the TSH response was significantly (P less than 0.05) lower in patients with IDDM. The Prl response to MTC was not significantly (P greater than 0.05) different within the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)