Kisspeptins are released in the hypothalamus and stimulate GnRH production. Interestingly, they are also under the control of photoperiod in seasonally-breeding animals…when days are longer kisspaptin is upregulated, increasing GnRH and stimulating the HPTA.
To what extent this applies to humans would probably be related to the extent to which humans are “seasonally-breeding.” And we are…somewhat (ever speculate about all those May birthdays?).
So get outside, get some sun and enjoy the summer…it may in fact be beneficial for your HPTA.
“In seasonally breeding rodents, short-day lengths results in a marked down-regulation of the HPG axis and subsequent gonadal regression, whereas exposure to long days induces an up-regulation of the HPG axis followed by gonadal recrudescence.”