Effects of amlodipine administration and withdrawal on rat pituitary gonadotropins

The study was aimed to observe the effect of amlodipine on rat pituitary gonadotropins after amlodipine administration and withdrawal.

It was an experimental study done at Army Medical College, National University of Sciences and Technology, Islamabad, Pakistan from 2009-2010. Sixty adult male rats were divided into groups A and B. Each group was further subdivided into two subgroups of 15 rats each; A1 (control), A2 (control recovery), B1 (amlodipine-treated) and B2 (amlodipine recovery). Amlodipine, 0.04 mg/kg body weight daily for fifty days was given by means of gavage to groups B1 and B2. Groups A1 and A2 were given vehicle (0.5 ml distilled water). After 50 days, rats in groups A1 and B1 were sacrificed and their serum LH and FSH levels were measured by Enzyme Immunoassay method. Vehicle and amlodipine were withdrawn in groups A2 and B2, respectively, and the rats were left for recovery to take place for another fifty days. The above procedure was adopted for the measurement of LH and FSH levels in the recovered rats.

Amlodipine administration for 50 days resulted in a significant rise in serum LH (p < 0.01) whereas serum FSH remained unchanged (p ≥ 0.05). Serum LH in amlodipine-treated rats returned to normal after amlodipine withdrawal (p ≥ 0.05).

Amlodipine causes a reversible increase in serum LH but it has no effect on serum FSH (Fig. 2, Ref. 17).