Thyroxine effect on intestinal Cl-/HCO3- exchange in hypo- and hyperthyroid rats.

Changes in transepithelial water and electrolyte transport as causative or contributing factors of the diarrhoea and constipation found associated with changes in thyroid physiology were studied. Albino Wistar rats were pharmacologically made either hypothyroid or hyperthyroid. After sacrifice, the small intestine was mounted in Ussing chambers in order to measure in vitro ion net fluxes under short-circuit conditions. Hypothyroid animals showed an increase in intestinal transit time, Cl- absorption (mainly due to an increment in its mucosal to serosal component) and residual ion flux (which is believed to represent HCO3- secretion) when compared with euthyroid animals. The hyperthyroid animals showed a decrease in Cl- mucosal to serosal transport. Furthermore, a significant correlation was found between serum L-thyroxine (T4) levels and both net Cl- transport (r = -0.74, P < 0.00001) and residual ion flux (r = -0.55, P < 0.005). These results indicate that the effect of T4 is firstly to inhibit Cl-/HCO3- anion exchange thereby influencing transepithelial flux transport and secondly to affect intestinal motility. Such inhibition was not found when T4 was acutely added to rat ileum, suggesting that the effect on electrolyte transport probably requires protein synthesis. In conclusion, the phenomenon observed in vitro could explain the clinical manifestations of constipation and diarrhoea in hypo- and hyper-thyroidism respectively.

Two interesting cases of transient neonatal diabetes mellitus.

Two cases of transient neonatal diabetes mellitus associated with anemia, macroglossia and umbilical hernia were studied in relation to the possible etiologies that have been postulated to be responsible for this syndrome. Both patients required insulin therapy for the control of their hyperglycemia but case number two needed to be treated for 14 months before glucose normalization occurred. This patient developed classical insulin dependent diabetes mellitus during our follow-up; the HLA typing showed DR4 allele.

Prognostic signs in the evolution of premature thelarche by discriminant analysis.

Since premature thelarche (PT) can be a first sign of precocious puberty (PP), the aim of our study was to identify simple items in the course of the first 6 months of follow-up that could help predict if PT would evolve to PP. Thirty-two girls with PT were studied. First evaluation included bone age (BA), basal estradiol, FSH, LH and prolactin. GnRH was performed in 15 subjects and BA was checked at 6 month intervals in 30. Based on clinical outcome after a mean follow-up of 33.4 +/- 16.5 (SD) months, patients were divided into 2 groups: Group I (G-I) included subjects whose breast development either remained unchanged, increased or regressed; Group II (G-II) included subjects who progressed to PP. The multivariate combination of the items which was able to best discriminate between the two groups was chosen in predicting the evolution of PT. The items considered included four variables available at the time of diagnosis [chronological (CA) at onset less than 3 years, basal FSH, basal LH and BA/CA ratio] and two additional variables after a 6-month follow-up (delta BA/delta CA and growth velocity); 88% of G-I and 14% of G-II had CA less than 3 yr. Basal FSH levels were elevated in both G-I (7.6 +/- 3.0 mIU/ml) and G-II (12.1 +/- 4.1) with respect to controls (2.6 +/- 1.2); however, approximately 20% of G-I had low FSH levels. Basal LH levels were consistently higher in G-II (8.0 +/- 1.3 mIU/ml) than in G-I (2.9 +/- 1.5) or controls (2.8 +/- 1.2). Although initial BA was advanced (greater than 2SD) in 21% of G-I and in all of G-II, an acceleration of BA was seen only in G-II. The mean growth velocity of G-I (44.1 +/- 31.5%) was significantly less than G-II (92 +/- 32%; p less than 0.0025). With the help of the discriminant equations derived from data obtained at diagnosis and during the first 6 months of follow-up, all subjects with isolated premature thelarche could be sharply distinguished from those who subsequently progressed to precocious puberty.(ABSTRACT TRUNCATED AT 250 WORDS)