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Title: Ultradian gonadotrophin profiles in patients with beta thalassaemia major
Author: Chatterjee, Ratna
Awarding Body: University of London
Current Institution: University College London (University of London)
Date of Award: 1992
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Gonadotrophin-hormone-releasing-hormone-Gonadotrophin hormone (GnRH-GTH) secretory dynamics of 30 females aged 11.2-23.8 years and 37 males aged 12.2-25.4 years with B thalassaemia major were studied over a period of 7 years by evaluating their ultradian gonadotrophin profiles. To obtain these profiles, blood was sampled at 20 minute intervals for 11-12 hours. Two populations of male and female adolescent thalassaemics were studied: patients with pubertal failure (The FP group) and patients who entered and completed puberty spontaneously during the study period (The SP group). Eighteen females and 28 males constituted the FP group, while 12 females and 9 males were included in the SP group. Twenty two healthy, non thalassaemic females and 22 healthy, non thalassaemic males (The Control group), matched for their stages of puberty with the aforementioned patients were studied for comparative purposes. As these subjects were the healthy siblings of the patients, they represented an ideal comparative population. Two non thalassaemic males and 2 non thalassaemic female patients with idiopathic hypogonadotrophic hypogonadism were also studied. The investigation aimed to determine whether thalassaemic patients with failed puberty had endogenous GnRH and/or GTH secretory insufficiency; if present, what was the degree of the deficiency and to what extent was it reversible. The second aim was to determine whether those thalassaemics with SP had a similar GnRH-GTH secretory pattern during their sexual maturation to that of the Controls. In general, the patients with SP resembled the Controls in their GTH peak parameters at the corresponding stages of puberty and showed a progressive increase in frequency and amplitude from prepuberty to full sexual maturation. This indicates that the patients followed the same physiological course of H-P maturation as the Controls with similar putative increments in the release of GnRH during puberty. A marked degree of heterogeneity in H-P function was found in the patients with failed puberty. Most had GTH pulses, others were apulsatile. Various pulse defects were observed, but the 4 major types of LH peak defects were abnormal size, low maximum GTH values in a profile (Maxi), low amplitude and developmental arrest. In both boys and girls, the FSH secretory deficiency was more profound than that of LH, being more severe in the boys than the girls. However, more boys were apulsatile for LH secretion than were girls (57% vs 28%). Although the pulse defects were essentially similar in both sexes, low Maxi was more common in the boys than the girls. Pulsatile GnRH infusion for three months achieved a partial or a total correction of the GTH peak parameters in the pulsatile FP patients indicating that they had a GnRH secretory defect. However, the apulsatile patients remained apulsatile despite prolonged infusion, indicating that these thalassaemics have an irreversible pituitary gonadotrophin defect. As a group, the apulsatile patients were found to be more iron overloaded, with much higher ferritin levels and they had a greater prevalence of organ dysfunction than the pulsatile patients, indicating that iron toxicity was likely to be a major factor responsible for the occurrence of the H-P defect in the thalassaemics studied.
Supervisor: Not available Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID:  DOI: Not available