A 17-year-old boy is brought to the office by his mother because of delayed puberty. The patient is 147 cm (4 ft 10 in) tall and weighs 50 kg (116 lb); BMI is 23 kg/m3. Physical examination shows a lack of facial and body hair, small testes, and poorly developed muscles. The patient speaks with a high voice. Neurologic examination shows anosmia. The results of serum studies are shown: Thyroid-stimulating hormone 2.1 µU/mL (N=0.5-5) Thyroxine (T4) 10 µg/dL (N=5-12) Growth hormone 8 ng/mL (N=1-9) Insulin-like growth factor-1 200 ng/mL (N=113-566) Total testosterone 3.5 nmol/L (N= 10-35) Luteinizing hormone undetectable Genetic testing shows a mutation in the KAL1 gene. The most likely cause of these findings is which of the following defects in the gonadotropin-releasing hormone (GnRH) system? A) Migration of GnRH neurons B) Release of GnRH from vesicles C) Response of pituitary GnRH receptor D) Reuptake of GnRH into GnRH neurons E) Transcription of the GnRH gene
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Adi S.
What is the endocrine disorder in this individual? Is the patient's delayed onset of puberty a primary or secondary disorder? Why? Why is HCG used in the treatment? Both FSH and HCG are needed in the treatment. Explain why? Case Study: Parents were concerned about their 16-year-old son for the following reasons: he had no deepening of his voice, scanty pubic and axillary hair growth, absence of beard and mustache growth, small penis, poor muscular development, and psychosocial immaturity. Laboratory evaluation indicated the following: Serum testosterone: 100 ng/dL Sperm count: 10 million/mL semen The following tests were performed: Clomiphene (a nonsteroidal, weak estrogen agonist that stimulates the release of gonadotropins) 100 mg/day for seven days: 0% increase in LH (50% is normal) Gn-RH (100 µg I.V.): 0% increase in LH in twenty minutes (300% is normal) HCG (5000 I.U., I.V.): 50% increase in plasma testosterone one to three days after injection This person was subsequently treated with FSH at 25-75 U three times/week and HCG as described above. Sperm count and testosterone levels were both near normal after two months of treatment, and primary and secondary sex characteristics appeared.
Supreeta N.
A 16-year-old girl comes to the office for a pre-participatory school sports examination. She plays on her high school soccer team and also frequently competes in local beauty pageants. The patient follows strict dietary limitations and exercises strenuously 2 hours a day. Onset of menses was at age 13, but her last menstrual period was 8 months ago. She otherwise feels well. Her height is 165 cm (5 ft 5 in) and her weight is 45.3 kg (100 lb), with a BMI of 16.6 kg/m². Physical examination shows a pale and thin girl with fine hair around her trunk, but the remainder is otherwise normal. Urine pregnancy test is negative. Which of the following is the most likely mechanism of her amenorrhea? Hyperprolactinemia Hyperthyroidism Hypothalamic suppression Primary pituitary dysfunction Primary ovarian failure
Sri K.
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