Table 4. Hill function parameters determined by fitting to matched samples of gonadal hormone/corticosteroid plasma levels.

x a	y b	e c	h d	n e	p f	Species	Ref.
corticosterone	progesterone	1	4.2	6	< 0.001	chicken	[117]
corticosterone	testosterone	5	3.9	4	< 0.001	chicken	[117]
cortisol	testosterone	28	5.2	6	< 0.001	rabbit	[118]
cortisol	LH	28	2.4	13	< 0.001	swine	[75]
cortisol	progesterone	23	8	8	< 0.001	humans	[119]
cortisol	testosterone	22	6	10	< 0.001	men	[87]
cortisol	testosterone	48	2.4	71	< 0.001	men	[86]
progesterone	corticosterone	32	3.5	11	< 0.001	chicken	[120]
testosterone	cortisol	17	7.3	6	< 0.001	rabbit	[118]
testosterone	cortisol	58	7.5	12	< 0.001	rabbit	[118]
LH	cortisol	50	7.5	6	< 0.001	rabbit	[118]
LH	cortisol	51	4.1	12	< 0.001	rabbit	[118]
testosterone	cortisol	23	1.5	71	< 0.001	male humans	[86]
progesterone	cortisol	64	3.8	23	< 0.001	female humans	[77]
progesterone	cortisol	65	8	6	< 0.001	female humans	[121]
		28‡	4.2‡

^aInput variable, expressed as hormone plasma level standardized on a 0–100 scale

^boutput variable, expressed as the input variable

^cHill function’s half-saturation constant

^dHill coefficient

^esize of the matched sample

^fcorrelation p-value

^‡median values.